


Simplistic Deals

by NihilismPastry



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, F/M, Female Reader, Harem, Orgy, Reader is in Asgore's Harem, Tentacle Sex
Language: English
Status: In-Progress
Published: 2016-11-09
Updated: 2016-12-05
Packaged: 2018-08-29 19:01:32
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,241
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8501656
Author URL: https://archiveofourown.org/users/NihilismPastry/pseuds/NihilismPastry
Summary: The Underground is a perilous place. The only way to survive is to either become strong, or to make deals with those who are stronger. You struck a deal with Asgore, the king of all monsters, and are now his personal harem girl. This gave you the opportunity to bump elbows with some of the most powerful monsters in the Underground, and to find a way out of the violent hell hole you'd found yourself in. It was all simple, really.





	1. The Daily Grind

**Summary for the Chapter:**

> Your daily life as a harem girl.

**Notes for the Chapter:**

> This is a story just for Dark_Crystal_Demon. This is the introductory chapter for it, but I hope you all manage to enjoy it.

You licked around the massive cock, your hands barely able to wrap around it. The sharp tug on your hair gave you encouragement to move as fast as your flame companion. Pleasuring King Asgore was always a work intensive task due to his gigantic cock. It couldn't fit in any of his harem girls, and it always took at least two to give him an almost proper blow job. Not that any of the spectators minded, all men in the upper circles who were watching you both while the king sat on his throne. You arched your back a bit more when you felt warm flames lick at your spine. What looked erotic to everyone else was a warning for you, your form hadn't been up to par.

The sound of doors opening, and footsteps shuffling against the tile distracted you for a moment. You glanced out of the corner of your eye to catch sight of a skeleton. Tall, lanky, and clothed in all black. He didn't spare you or your partner a second glance as he came up to the throne. Over the musk and sweat, you could smell something metallic and cold. He must have just left his lab, and hadn't bothered to go back home to scrub himself clean of the chemicals. 

He bowed before the king, an elaborate and almost mocking gesture, before straightening himself and using his hands to speak.  ' _My King, I apologize for my tardiness, but I had important work in the lab that needed my attention_.'

Asgore waved a hand. "You're fine, Dr. Gaster. Truth be told, if it was anyone else, I would have your skull." He snapped his fingers, and you and your companion stood up from the throne, your own knees popping. For the first time Gaster glanced over to you, but looked away when you tilted your head. "Both of you return to your wing of the palace."

You both bowed politely before leaving the stone hall. The doors were opened by two guards, both looking your naked bodies over with an appreciative eye, but didn't dare touch. As soon as the doors closed behind you both, the violet elemental took your hand and hurried down the hallway. The wooden floorboards creaked under your hurried steps as you both went to your wing of the castle. 

"Thank goodness the Doc finally came," The lavender flame elemental said. "I thought my tongue would fall off! I wish he wasn't always late to everything. I swear he does it on purpose."

You shrug, and gripped the lovely carved handrails as you both went downstairs. "He's a busy man. Besides, I thought you liked getting covered in cum, Ember?"

The flame elemental nodded."I do, just not at the cost of my tongue. it's not natural like yours and the other girls."

"What about Ame?"

"She's a water elemental. Doesn't count."

You opened up the large wooden door, and the spicy smell of cinnamon flooded your nose as you entered the harem wing of the palace. Ten other women lounged around on chairs and over stuffed pillows, all of them naked. A few of the girls looked up from what they were doing as you entered the room, but relaxed when they realized you weren't the King. Ember pat your shoulder, and went to a small rabbit girl, giving her a quick kiss on the cheek. You went to an empty chair in front of a cluttered vanity, and sat down with a low moan. The king had used you thoroughly the last three days. It was coming up on your 'fall anniversary', you wondered if it had anything to do with that.

You frowned when you noticed a violet handkerchief stuffed in the corner of the vanity. You snatched it up, and a small note fell onto your lap. You glanced around, but didn't notice any prying eyes. Most of the girls were crowding around Ember as she regaled them of what happened, the rabbit girl on her lap. The only one that wasn't, a stern looking spider woman, was reading a book with her back to you. You twisted back around and unfolded the cream colored stationary, just to find a message written in chicken scratch. A soft smile curled over your lips as you began to rip it up. When the page was as small as it could be, you stood up and went over to the fire. Without any pomp, you threw it into the lavender flames. 

You then went back over to the other girls, a small bird like monster scooting over for you. A few of the other girls cracked jokes about your low stamina, while some gave you tips on your form. Altogether it created a fun atmosphere, a fine distraction from the note you had just received.

* * *

At night the doors of the room were locked by the King himself. He would bid each of you good night with a tender kiss to the forehead, before locking the door to the room, taking three of the girls with him. You were thankful he spared you that night as you laid curled up in a thick blanket. The other girls in the room quickly fell asleep, blanketing the room in soft snores. When none of the girls woke up, or the King returned, you stood up and went over to the vanity. You grappled around for a moment, bumping g against perfume bottles and brushes, before your fingers curled around the violet handkerchief. You snatched it up, and pressed it to your mouth, whispering words in a guttural language you didn't actually understand. 

 As the words were whispered, a dark smoke curled around you, and before you knew it you were blinking under an intense light. It was colder here, your nipples already erect, and your arms covered in goose bumps. The room was large and filled with all sorts of metal instruments on high metal tables. Hunched over one of them was the skeleton from earlier. Papers covered his table, and there were pen marks all over them. He hadn't seemed to notice you yet, a good thing you supposed. You padded over to him, and wrapped your arms around his slim hips bones. He glanced up from the papers, his body relaxing when he caught sight of you. "I came liked you asked, Dr. Gaster."

 He twisted around in your hold, his fingers already moving to form words. ' _Thank you for coming on such short notice. It is a matter of up most importance_.'

"Is that so?"

He bent down, pressing his teeth to your head, and yanking your hips closer to his own. "I must know how many times I can fuck you before morning."

He picked you up and slammed you against a nearby table. You whimpered from the pain, but it only seemed to egg him on as he ground his pelvis against your own. Your mouth opened, and he pressed his teeth to it, slipping his slimy tongue into your mouth. You gasped and arched into him, his hands gripping harder into your soft skin. You could smell the blood, and knew his hands would be stained with it. You separated your mouth from the eager doctor. "No marks, that was part of the deal."

"Of course, I'm sorry, dear heart." 

You wrinkled your nose at the nickname, but kissed him again anyway. You didn't come to him for love and affection, you came to fulfill a deal. 

And fulfill it you did.

Once against the table, and twice on the floor. By the time Gaster was finally spent, you thought you were going to pass out on him. The man after had ridiculously high stamina, and an equally high libido with no other outlet than you. If it wasn't for your no marking rule, you'd probably be covered in bites and bruises from the sheer intensity of the fucking, and his own sadistic tendencies. You sat up, and untangled yourself from the skeleton, pain shooting down your back and thighs. "I expect results next time I come back."

Gaster chuckled, a deep sound that had a raspy quality to it. He lifted his hands and lazily signed. _'I find it amusing that a human whore is making demands of me. We entered a deal, and I have every intention to honor it_.' 

"I'm sure you do, now send me home." Magic crackled in the air, and a series of smooth bones stabbed into the ground in a circle around you. Red light transferred from one bone to another, before a black darkness rose into the air and engulfed you whole.

When you appeared in the harem room again, your soul felt heavy and hallow. 

**Notes for the Chapter:**

> Ta-Da! I hope you all enjoyed it. So, Reader and Gaster are doing things they shouldn't, and it'll probably get them killed. And magic is super flashy here, kinda like in the game. I actually like writing flashy magic. XD
> 
> Know what isn't flashy? My tumblr! http://nihilismpastry.tumblr.com


	2. What was Supposed to Be Normal

**Summary for the Chapter:**

> A trip to the bathhouse takes an unexpected turn.

**Notes for the Chapter:**

> I ended up revising the end, that's what took so long. But now I'm back! So I hope you enjoy this chapter!

The steam from the bath nearly clouded the entire room, and your grip on the king's arm tightened. The warm tiles were far too slippery, and your sudden impaired vision was not helping your confidence. Truth be told, you didn't like the bathhouse, it was stuffy and made you sleepy. It was hard to do your job when you were constantly under threat of falling asleep and drowning. But the king had asked you, Ame, and the bathhouse owner to accompany him today. You were lucky he hadn't invited any of the nobles, you didn't think you could take sucking off the king and taking it from behind today, not after your stint with Gaster the night before.

It had taken several baths, and enough perfume to kill a bloodhound to hide Gaster's scent. The interesting thing about monsters, was that all of them had a good sense of smell, but what they were smelling was actual magic. They could differentiate between the intent of the magic used, and since you had fucked Gaster without Asgore, the king would have been able to smell whatever Gaster's intent was at the time. And knowing him, you were sure it was something that would make Asgore suspicious. 

The monster let go of you, allowing you to go to the changing room with Ame. "We'll be at the northern bath. Do not take too long, we will have to return to the palace soon."

You both muttered an affirmative as Ame opened up the door to the dressing room. When it was closed behind you both, Ame erupted into giggles, her dark blue skin becoming paler around her face. "Did you see the bath owner? She's so beautiful, right?"

You shrugged, and began unbuckled your cloak. You weren't quite sure what to say about a woman who had a giant, jade clam shell for a head. Honestly, it was probably better not to say anything at all. "You should get undressed, if you don't start now, we'll never go out there."

"Oh, of course!" She began to untie her own cloak. "But she's just so lovely. The cutest smile!"

Strangely enough, all the harem girls were expected to wear an impressive amount of clothing when leaving the palace. Between your skirt, the blouse, and cloak you were expected to wear, you felt more like a nun than a glorified whore. "Don't get too attached, isn't that what Muffet tells you?"

The water elemental nodded, the small sphere hovering above her head bouncing somewhat. "I suppose."

She put her boots next to your flats, before turning to you, finally naked. You folded your skirt for the second time, and gave a low sigh, mentally preparing for what you had to do. "Do you know what he wants with her, anyway?"

"Maybe to watch? You know he's quite the exhibitionist." Ame opened up the door for you, and you both headed to the specified pool. The tile was warm under your bare feet, and you the warm air against your skin felt almost soothing. "I just hope we have enough time to talk to her later. The last bath house owner was a real cad. He used to speak so rudely, and would imply that we were dirty just because we're harem girls."

Your nose wrinkled, but you didn't say anything about that. To be fair, having sex in a public bath house was very unhygienic. The man must have had to do a lot of work to get it all cleaned up after the king and whoever he brought left. 

You pitied him.

 Your thoughts came to a stop as Ame opened up a stone door set with stained glass windows. Inside was a giant pool of water that had steam rising from it. The king sat on the stone steps, his white fur almost sparkling with red magic. The bath house owner sat on the other side of the bath, just her feet in the water. Ame walked over to the king, and sank down into the water beside him. The water around her swirled around, but didn't sink into her already liquified body. Her fingers carded through the king's thick fur, and she leaned up pressing her featureless face to his mouth. As they 'kissed' you dipped your feet into the water, and walked down the first four steps. 

You sank to your knees in front of the king, and gripped his magical member. It twitched under your hand, and you heard the king groan. Your fingers glided upward, the fingernails lightly scratching along the red surface. You repeated the process a few times, before licking the sides. It was harder to do this all by yourself, but the king was too engrossed in sucking the giant breasts Ame had formed for him. 

As you licked up and down the shaft, you felt a heavy pawn on your head, playing with your wet locks. You looked up at the king through your eyelashes, and was surprised to see him gazing down at you. You licked up to the top, before removing your tongue completely, and pulling yourself out of the water. Asgore detached himself from Ame, and leaned down to press his mouth to yours. He tasted like raspberries and tea, a flavor you truly enjoyed. 

Ame reached down and grabbed his cock, using her water to cover it entirely. He growled and kissed your deeper, gathering you into his lap. As his tongue roamed around your mouth, you felt Ame press her body close to yours, and something cold envelop around your breasts. You gasped when they tightened, separating your mouth from the king's. A quick glance down proved your suspicions, Ame was using her tentacles to massage your breast, she was even creating a third one on her pelvis, the tentacle inching towards your pussy. 

"Master, may I?"

The old goat chuckled as he ended the kiss. "Yes, fuck this little slut for me."

You gasped when you felt it slide into your pussy, the temperature quickly adjusting so it was bearable. The tentacle itself wasn't the large, but it was nice and long, the perfect fucking size. Ame moaned and leaned heavier against you, the tentacle sinking in and out of your cunt. It was so good, the fucking in your mouth and pussy. Your fingers curled into the king's chest, your moans coming out as a garbled mess. You wished Ame would get rougher with you, it wasn't hard enough, you needed more.

As the fucking wore on, and your orgasm drew closer, you felt a numbness begin to settle into your core.The excitement ofthe moment began to fade into nothing, and you felt needle like jabs in the back of your skull. You gripped the king a little tighter, breathed a little deeper, but nothing was helping. It was like you were sinking into a tunnel, and everything was sliding away from you and into its own world. At the edges of your vision, you saw symbols. They were both familiar and unfamiliar, almost taunting you as you spiraled deeper into the numbness. 

A sharp cry from behind you grabbed your attention, and dragged you from the deep end. You twisted around, and saw the clam woman fingering a conjured pussy, her thighs shaking and head thrown back. Ame shoved her tentacle deep into your body, and you felt warmth spurting inside of you. The feeling came back with a vengeance, and before you knew it, you felt your eyes closing and your sense of self slipping away. 

* * *

You moaned and twisted around, something cool and smooth brushing against your body. It felt like cotton, but you hadn't felt any since you were with Toriel. You opened your eyes, and a cold light shone in them, making you blink a few times. When your vision cleared, you noticed you were in a painfully white room. There was no furniture in there, just tiles on the floors and walls. You were laying on a metal bed, with sheets covering your naked body. There was a lamp fixed to the coloring, and it was far too bright for you to be comfortable. 

It looked like you were in some kind of hospital. The thought made your nose wrinkle, and push back the sheets. You wobbled to your feet, and went to the door, peeking your head out into the hallway. It was just as white as the room, but a few monsters were milling around, though none you recognized. It looked like Asgore really did take you to some kind of hospital. And to think a place like the Underground even had one.

Looks like you learn something new everyday. 

Your thoughts ground to a halt when a short skeleton monster went down the hall. He was small, as far as monsters went, and had a smile etched into his skull. You had only seen one skeleton monster since your fall into this place, you had always thought Gaster was the only one. He began to slow down when he got to your room. "you're up?"

"..."

He came closer to you, revealing that he was only a few inches taller than you, and carefully tapped your skull with his knuckles. You hissed and recoiled from him. "looks like the damage is still present, just cosmetic clean up. gotta fix ya up myself then."

You backed yourself up to make room for the skeleton, before following him into the room. He gestured to the bed, and you obediently sat down. Without looking away from you, he raised his hand and a bright fire grew in his hands. It began to morph until it was a faint green. 

"Is that healing magic?"

"yeah, ya gotta problem with it?"

You shook your head, not sure why his tone had become so hostile. You hadn't even known healing magic existed until just now. Well, it was better than needles or pills. The skeleton brought his hand to your skull, and let the flames lick along the damaged area. "Did I fall in the bath?"

"yup. almost bled out on the steps. lucky you're not dead."

"Oh..." You blinked as his words began to sink in. "Exactly, how do you know I was going to bleed out? Aren't monsters made of magic?"

"it's my job to know about humans." He said. "now shut up, gotta concentrate."

You'd almost died? But that didn't make any sense, you weren't that far from the steps, and the water would have slowed you down in the first place. You'd have to cover this with Gaster, something was seriously wrong now. And he probably had something to do with it. 

**Notes for the Chapter:**

> So, we're coming close to when things will actually be explained, like what's going on and stuff. Originally Gaster was supposed to work on Reader, not Sans, and they would reveal some of the backstory and plot. But then I thought that it wouldn't make sense considering what's going on in the story, so I ended up changing it. Editing is so time consuming. 
> 
> Know what isn't time consuming? My tumblr! http://nihilismpastry.tumblr.com


End file.
